Northrop Grumman Systems Corporation

Kenneth M Zick

Aaron A Pesetski

David George Ferguson

Anthony Joseph Przybysz

Robert T Hinkey

Sergey S Novikov

One example includes an Ising machine system. The system includes a plurality of ring oscillators that are each configured to propagate an oscillation signal. Each of the ring oscillators can be cross-coupled with at least one other of the ring oscillators via a respective one of the oscillation signals to provide a respective phase coupling between the respective cross-coupled ring oscillators. The system also includes an Ising machine controller configured to generate control signals corresponding to parameters of an Ising problem and including a plurality of delay selection signals. The Ising machine controller can provide at least one of the delay selection signals to each of the ring oscillators. The delay selection signal can be configured to set a variable propagation delay of the ring oscillator to control the relative phase coupling of each of the ring oscillators to each of the at least one other of the ring oscillators.

Ring oscillator-based Ising machine system

One example includes a tunable current element. The element includes a first magnetic flux component that is configured to exhibit a bias flux in response to a first control current. The bias flux can decrease relative energy barriers between discrete energy states of the tunable current element. The element also includes a second magnetic flux component that is configured to exhibit a control flux in response to a second control current. The control flux can change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states, such that the magnetic flux component is configured to generate a hysteretic current that provides a magnetic flux at an amplitude corresponding to the energy state of the tunable current element.

Magnetic flux source system

One example includes a magnetic flux source system that includes a tunable current element. The tunable current element includes a SQUID inductively coupled to a first control line that conducts a first control current that induces a bias flux in the SQUID to decrease relative energy barriers between discrete energy states of the tunable current element. The system also includes an inductor in a series loop with the SQUID and inductively coupled to a second control line that conducts a second control current that induces a control flux in the series loop to change a potential energy of the discrete energy states of the tunable current element to set an energy state of the tunable current element to one of the discrete energy states to generate a current that provides a magnetic flux at an amplitude corresponding to the energy state of the at least one tunable current element.

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Baltimore, MD, United States of America

Kenneth M Zick